1. Field of Invention
The present invention relates to chemical handling apparatus and more particularly to a station for handling a variety of chemical processes and operations.
2. Description of the Prior Art
A great number of industries utilize chemical processing stations. These stations are primarily utilized for batch processing of various components or materials.
An industry in which the use of chemical processing stations has become particularly important is the semiconductor wafer industry. Silicon semiconductor wafers are created and treated utilizing a number of chemical processes. The wafers are typically processed in a batch manner. That is, a relatively small number of wafers are hand or machine processed through a variety of small chemical baths. This limited volume technique is desirable due to the fragility of the wafers. It is also desirable to maintain the best possible quality control by individual handling and inspection of the wafers.
One of the major difficulties involved in chemical processing stations for the semiconductor industry is that a large variety of different processes may be required. Depending on the type of wafer desired, the number and type of chemical processes through which the wafer is put differ greatly. Consequently, a chemical processing station intended to handle the complete processing of varying types of wafers must be very flexible as to the different chemical processes which can be conducted.
A further difficulty encountered in the chemical processing of semiconductor wafers is that many of the chemicals utilized are extremely toxic and/or very corrosive to ordinary container materials. One of the chemicals frequently utilized in this industry is hydrofluoric acid (HF). HF is an extremely toxic and corrosive chemical which is very dangerous for an operator to handle and will also corrode and eat through ordinary container materials such as all metals and glass. Various solvents utilized in the processing industry, such as methyl-ethyl-ketone (MEK) have the opposite effect of being highly destructive towards plastics and other synthetic materials. Consequently, the choice of material and arrangement of chemical processing areas within the stations are of particular importance.
The toxicity and volatility of many chemicals also creates a problem in that various chemicals must be vented to prevent their dispersion into the air and particularly into the work area in which a processing technician must work. For this reason, a chemical processing station must include ventilation means for drawing the toxic fumes away for safe processing. Care must also be taken that mutually reactive fumes, such as certain strong acids and certain organic solvents, are not mixed in the fume removal apparatus.
The attempts of the prior art to deal with these problems have been, in the main, haphazard. A typical chemical processing station will be custom built for the particular application and will be constructed of the particular materials and in the particular configuration required for this specific application. This type of custom production of each individual work area greatly increases manufacturing costs while limiting usefulness of each area to a particular process.
Another difficulty encountered by prior art chemical processing stations is that mutually reactive chemical reagents must usually be separated by a significant distance due to fume interaction and spillage interaction. This is a major impediment to efficient processing and can again increase cost of manufacture since each element must be separately manufactured.
A further disadvantage to the prior art method of constructing chemical processing stations is the lack of flexibility and the accompanying difficulty of rapid replacement. When a portion of a custom built processing area malfunctions or needs to be replaced or repaired, it is difficult to quickly make such replacements and repair since the new component must be custom manufactured. Also, the stations are frequently constructed such that the various components are difficult to reach and are thus difficult to replace. Furthermore, advancing technology frequently provides new and different process techniques which require complete replacement of prior equipment.
No prior art chemical processing stations for the semiconductor wafer industry are modularly interchangeable, that is, designed such that one area of the station may be rapidly replaced and/or interchanged with other areas. None of the prior art attempts adequately solve the aforementioned problems which are present in the semiconductor industry.